Artificial-tooth facing with backing adjustment.



F. E. HART.

ARTIFICIAL TOOTH FACING WITH BACKING ADJUSTMENT.

APPLICATION FILED MAY 10. I915.

Patented Oct. 19, 1915.

(II/Viewing FRED E. HART, OF SAN FRANCISCO, CALIFORNIA.

ARTIFICIAL-TOOTH FACING WITH BACKING ADJUSTMENT.

Specification of Letters ?atent.

Patented oer. is, tars.

Application filed May 10, 1915. Serial No. 27,262.

To all whom it in my concern: 7

Be it known that I, F RED E. HART, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and useful Improvements in Artificial-Tocth Facings with Backing Adjustme" ts, of which the following is a specification. a.

this invention relates to that class of artificial teeth wherein facings, of porcelain or the like, are detachably secured to a metallic backing by which they may be soldered or otherwise attached to crowns, bridges, etc.

When the facings are subjected to the heat necessary to solder or cast metal backings thereto, the porcelain is very liable to become cracked or checked by the expansion and contraction of the heated metal and the principal feature of myinvention is to provide a porcelain facing that can be readily removed from the backing during the operation of sclclcring or'casting the crown or lr'dge thereto.

An ther object is to provide a facing that may be readily attached to the crown or bridge without removing the case from the morth, where it is necessary to replace a facing that has-become broken or for any other reason.

A further object of my invention is to provide an attaching means that will'firmly support the facing and brace it against lateral strains.

(ther objects will be apparent from the following description taken in connection with the accompanying drawings, in Wl1lCl1-- Figures 1 and 2 are vertical secti ns through a facing embodying my invention and showing the manner of adjusting the support thereto: Fig. 3 is a similar sectional view showing the manner in which the facing and its attachment are crowned or cut a ay in preparing it for a particular case; Fig. shows the same with the support in position and the metal backing bent to con form t the back of the facing; Fig. 5 shows the manner in which the facing may be ground preparatory to tipping with the metal backing; Fig. 6 is a sectional View showing the manner of attaching the facing to crown; Fig. 7 is a cross section on the line T-? of Fig. 4; Fig. 8 is a perspective view of the section shown in Fig. 4; and

Fig. 9 is a rear elevation of the facing shown of the facing, a smaller one necessitating a groove extending nearer to the edge than a larger one. The size of the groove 1s also dependent upon the s1Ze of the facing a small facing requiring a smaller groove than V a large one. The upper or incisal end of the g oove is preferably curved in the manner illustrated.

Crossing this groove at right angles to'the longitudinal axis of the facing is a platinum pin which is baked into the facing during the process of its construction. This pin is preferably in the form of a stick with the pron gs flaring outwardly and extending well. into the body-of the porcelain facing as illustrated in Fig. 7. This provides a firm anchorage at each end while perm'tting the outer side of the pin to be nearly flush with the back of the facing. In some cases it is desirable to form this pin of two separate prcngs which meet over the groove in order that the porcelain may not-be subjected to undue strains during the baking process due to any unequal expansion and contmction of the metal and the pcrticns may then be rnited and made integral without injury to the facing. In order to removably secure the facing to the thin gold sheet 7 which foans the backing. I provide a T-shaoed post having the stem potion 9 extending through an aperture in the loackirg so that it may be initially adjusted with relation thereto and the head portirn which is of the proper size to fit into. the groove, having the sho'ter end 9 adapted to hook under the anchor pin 5 and the longer end 9 extending throughout the length of the groove to the base end. This supporting post may be formed of platinum or any suitable alloys of gold or silver, while the backing 7 may be of pure gold, and alloy of gold or of lat num.

The head of the pest is first placed in the groove and slid longitudinally thereof until lOO the pin ,5 rests inthe angle between the hook end 9* and the stem 9. The sheet backing 7 is then pushed toward the head of the stem until it bears upon the rear face of the facing as indicated in Fig. 2.

It is usually necessary to grind or cut the artificial facings or teeth which are selected from stock sizes in order to fit them to the mouth of any particular patient. I have indicated in Fig. 3 the next step after that shown in Fig. 2, indicating in dotted-lines the portion of the facing which is ground away and the manner in which the end 9 of the post must be correspondingly cut off. After this is done the backing is bent at the proper angle to conform to the base or gingival end as indicated in Fig. 4. In some cases it is desirable to tip the incisal end of the facing with the metal backing and I have shown in Fig. 5 the manner in which the facing is groundin preparation for the tipping. In such cases it is also necessary to slightly bevel the hook end of the pin, the part which is cut away being indicated in dotted lines, in order to facilitate the introduction of the post into the groove after the backing has been bent over the tip in the manner shown in Fig. 6. After the parts have been thus properly shaped and fitted, the porcelain facing is removed and the backing with the attached supporting post is soldered or otherwise attached to the bridge or crown. In Fig. 6 I have indicated in dotted lines the outline of a gold crown 10 with its attaching pin 12, showing the manner in V which the gold is cast to the backing and the 7 process of soldering or casting the metal to thebacking,-the latter having been burnished in the usual and well known manner. The whole is completed by'the final step of slipping the facing over the post, the parts being firmly held in position by the use of cement 14: as usual.

' My invention provides an exceedingly strong and rigid construction. The lower end of the post portion 9 bears firmly upon and is supported by that part of the backing which is bent against thebase or gingival end of the facing and as these parts meet at an angle to the axis of the post, any tendency of the post to rotate is prevented by the pressure of the end 9 against the ingroove 3 and bears throughout its length against the bottom of the groove and thus prevents any tendency of the facing to a lateral or rotary movement about the stem 9 of the post. The projection of the stem 9 through the backing plate permits a very strong attachment when the gold is melted onto it in the course of the crown or bridge construction. The groove is merely wide enough to receive the head of the post and consequently does not weaken the body of the facing.

lVhile I have described in detail the particular construction illustrated in the accompanying drawings for the purpose of fully disclosing an embodiment of my invention, I am aware that various modifications may be made therein without departing from .the scope of my claims and within the spirit a metal pin baked into said facing and extending transversely across said groove, a sheet metal backing conforming to the rear side of the facing, a supporting post projecting from said backing and having a T- head adapted to fit within said groove with one part extending back of said pin and the other part hearing at its outer end upon the backing.

2. An artificial tooth comprising a facing having its rear side substantially parallel with the front side and having the base or gingival end extending obliquely thereto and forming an acute angle with the front side, said rear side being provided with a longitudinal groove, a metal pin baked into said facing and extending transversely across said groove, a sheet metal backing conforming to said rear side and to said oblique end, a supporting post projecting from said backing and having a T-head. adapted to fit within said groove with one part extending back of said pin and the other part bearing at its outer end against the oblique portion of the backing.

In testimony whereof I aflix my signature in presence of two witnesses.

FRED E. HART.

lVitnesses:

G120. T. Tnownnmon, ELLA L. SMITH.

' Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. C. 

